Joint lock ring system for lined pipes

ABSTRACT

A joint ring, system for lined pipes includes a first pipe and a second pipe joined end-to-end, each pipe having an interior lining covering substantially all of an interior wall of the respective pipe. A first ring is disposed within and substantially flush with the joined end of the first pipe, and a second ring is disposed within and substantially flush with the joined end of the second pipe. The first ring is configured to create a first circumferential pressure seal against the interior wall of the first pipe, and the second ring is configured to create a second circumferential pressure seal against the interior wall of the second pipe. At least one of the first ring and the second ring is configured to create a pipe joint pressure seal against the other ring.

CROSS-REFERENCE TO RELATED APPLICATIONS

Priority is claimed to U.S. provisional application No. 61/775,749,filed Mar. 11, 2013, the disclosure of which is incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The field of the present invention is systems and methods for joininglined pipes, and particularly cement or rubber lined pipes.

BACKGROUND OF THE INVENTION

Within industries that use lined pipes, among winch is the miningindustry, steel pipe is manufactured and may he installed for multiplepurposes. Steel pipe can be connected or joined in a variety of waysdepending on the application and design requirements. One of thestruggles that currently exists with pipes having internal cement orrubber linings is obtaining quality welds when connecting two pieces ofbeveled end steel cement-lined or rubber-lined, pipe. Currently when twosections of pipe are joined together, beveled end against beveled end,and the initial weld pass (referred to as the “root pass”) directlycontacts the cement or rubber lining, resulting in both contamination ofthe welding and weakening of the cement or rubber during the root pass.The result is that the completed weld joint strength is reduced dire tothis contamination. Also this joint type does not allow a qualitymechanical or nondestructive test of the completed welded joint.

In order to overcome this problem with concrete contamination, thethickness of the pipe wail has been increased by about 20% or greaterthan necessary for most applications. Such a solution results in about a20% or greater increase in the cost of materials. A more cost effectivesolution to preventing concrete contamination when joining fined pipesby welding is therefore desired.

SUMMARY OF THE INVENTION

The present invention is directed toward a lined pipe and a system andmethod for joining such lined pipes. The pipes may be cement-lined orrubber-lined carbon steel pipes, although those of skill in the art mayrecognize uses for the system with other types of pipe and with othertypes of lining,

In a first separate aspect of the present invention, a ring is disposedwithin and substantially flush with the end of a pipe having an interiorlining covering substantially all of the interior wall of the pipe. Thering forms a circumferential pressure seal against the interior wall ofthe pipe, and the radial thickness of the interior lining and the firstring are substantially the same.

In a second separate aspect of the present invention, the systemincludes two pipes joined end-to-end, each pipe having an interiorlining covering substantially all of the interior wall of the respectivepipe. One of two rings is disposed within the joined end of each pipe,with each ring being substantially flush with the respective joined end.Both rings are configured to create a circumferential pressure sealagainst the interior wall of the respective pipe. In addition, at leastone of the rings is configured to create a pipe joint pressure sealagainst the other of the rings.

Several different enhancements may be incorporated into this system,either alone or in combination with other enhancements. As oneenhancement, the radial thickness of each ring ma be approximately thesame as the radial thickness of the lining of each respective pipe. Asanother enhancement, The circumferential pressure seals may be formed byan O-ring set in a circumferential groove in the outer circumferentialsurface of the ring, or they may be formed by a weld. As anotherenhancement, the inner circumferential surfaces of the rings may includea coating configured to resist corrosion when exposed to a fluidtransported within the pipe during use.

In a third separate aspect of the present invention, a method ofconnecting lined pipes includes inserting one of two rings into therespective ends of two pipes to be joined end-to-end. Each ring isinserted so that it is substantially flush with the end of therespective pipe, and each ring forms a circumferential pressure sealagainst the interior wall of the respective pipe. With the ringsinserted, the two pipe ends are welded together along an exteriorcircumference of the pipes. This method may be enhanced by use of a twopiece clamp configured to seat the rings within the ends of therespective pipes as the two clamp pieces are drawn together.

In an fourth separate aspect of the present invention, any of theforegoing aspects may be employed in combination.

Accordingly, an improved joint lock ring system is disclosed. Advantagesof the improvements will be apparent from the drawings and thedescription of the preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe exemplary embodiments, will be better understood when read inconjunction with the appended drawings. It should be understood,however, that the invention is not limited to the precise arrangementsand instrumentalities shown in the following figures:

FIGS. 1A-E illustrate a first joint lock ring system;

FIGS. 2A-C illustrate a second joint lock ring system;

FIGS. 3A-C illustrate a third joint lock ring system;

FIGS. 4A-E illustrate a fourth joint lock ring system;

FIGS. 5A-D illustrate a fifth joint lock ring system;

FIGS. 6A-C illustrate a sixth joint lock ring system;

FIGS. 7A-D illustrate a first half of a pipe clamp assembly;

FIGS. 8A-C illustrate a second half of a pipe clamp assembly; and

FIGS. 9A-D illustrate an alternative embodiment of the first half of thepipe clamp assembly.

DETAILED DESCRIPTION OF THE INVENTION

Turning in detail to the drawings, FIGS. 1A-E illustrate a joint lockring system 101 suitable for use with a cement lined pipe 103. A cementlined pipe is described herein as an exemplified embodiment, and thoseof skill in the art will recognize that the same system may he used withany type of lined pipe, whether the lining be formed by cement, rubber,or any other materials. Thus, it is to be understood that The systemincludes two rings 105, 107, each inserted into the respective ends 109,111 of the cement lined pipes 103, each ring being flush with therespective end of the pipe. The cement lining 113 lines the inner wall114 of the pipes 103 between the rings 105, 107. Each ring 105, 107 ispreferably formed from carbon steel, and preferably of the same steelgrade and properties as the pipe, that is rolled to a specified diameterand machined to a specified tolerance. The diameter and tolerance are amatter of design choice, depending upon the size and wall thickness ofthe pipe into which the ring is to be placed.

Each ring 105, 107 includes a circumferential groove 115 in the outercircumferential surface 117, into which is placed an O-ring 119, whichseals against the internal pipe wall 114. This first O-Ring 119restricts fluid within the pipe from reaching or affecting the weld zoneof the welded joint 121. The first ring 105 includes an anterior sidecircumferential groove 123 in which another O-ring 125 is seated. Thissecond O-ring, 125 creates a pipe joint pressure seal against the secondring 107, as shown in FIG. 1A, when the pipes 103 are aligned and weldedtogether, and it likewise restricts fluid within the pipe from reachingor affecting the weld zone of the welded joint 121. The O-rings arepreferably formed from a fluorocarbon elastomer rubber, such as theViton® brand sold by E.I. du Pont de Nemours and Company of Wilmington,Del.

The anterior side O-ring locations are expected to hold line pressure inexcess of 2000 PSI in the event of a. weld failure. The benefit providedis a dual sealing system that prevents fluids from potentially escaping,into the environment in the event of a weld failure.

Internal surfaces 127 of the rings 105, 107 that contact the fluidwithin the pipes are coated with a wear resistant, non-conductiveceramic coating 129. This coating 126 preferably extends entirely alongthe entire posterior surface 131 of the rings 105, 107 and partiallyalong the anterior surface 133, at least to approximately where the0-ring 119 contacts the anterior surfaces 133 of each ring 105, 107 toform the pipe joint pressure seal. Preferably, an aluminum oxide, Al2O3(such as is available from Accuratus Corporation of Phillipsburg. N.J.),coating is applied by a plasma spray process to a thickness of about 15mils to 20 mils. Such a coating is highly resistant to abrasion, heat,and corrosion.

A second joint lock ring system 201 is illustrated in FIGS. 2A-C, Thissecond system 201 is like the first, except for instead of an O-ringbeing placed in the side circumferential groove 115 of the first ring105, a flat, flexible gasket 205 is placed therein. This flat flexiblegasket is preferably of the type obtainable from Oarlock SealingTechnologies of Palmyra, N.Y., particularly the Garlock BLUE--GARD 3400model of flexible gasket.

A third joint lock ring system 301 is illustrated in FIGS. 3A-C. Thisthird system 301 is also like the first, except for this system 301 doesnot include a protective ceramic coating, and instead of an O-ring beingplaced in the side circumferential groove of a ring, the inner surface305 of each ring 303 is formed with one or more interlocking grooves307. These interlocking grooves 307 are formed to be complementary tosimilar interlocking grooves 309 formed on a protective circumferentialliner 311, which is preferably molded with Viton® fluorocarbon elastomerrubber. The interlocking grooves 307 of each ring 303 and theinterlocking grooves 309 of each liner 311 may take a shape according,to design preference, with the purpose being that the respective grooves307, 309 serve to hold the liner in place on the inner surface 305 ofthe ring 303. The anterior and posterior edges 313, 315 of each liner311 extends slightly beyond the edge of the ring 303 so that a seal canbe created with the cement liner on one edge 313 and with the secondring, on the other edge 315. These sealing points prevent fluids frompotentially escaping into the environment in the event of a weldfailure.

A fourth joint lock ring system 401 is illustrated in FIGS. 4A-E. Thisfourth system 401 incorporates features of both the first system and thesecond system. in this fourth system 401, the first ring 403 includes ananterior side circumferential groove 407 in which an O-ring 409 isseated, and a liner 411, which is again preferably molded with Viton®fluorocarbon elastomer rubber, is affixed the inner surface 413 of eachring 403, 405. Through holes 415 are formed around each ring 403, 405,the liner 411 extends into the through holes. The through holes 415 areformed to have varying diameters, and the liner 411 is formed withfingers 417 having a complementary shape as compared to the throughholes 415 to aid in holding the liner 411 in place on each ring 403, 405The liner 411 covers the entire posterior edge 419 of each ring 403, 405so that a bonded seal can be created with the cement or rubber lineradjacent the posterior edge 419, This sealing point prevents fluids frompotentially escaping into the environment in the event of a weldfailure.

A fifth joint lock ring system 501 is illustrated in FIGS. 5A-D. In thisfifth system 501, the first ring 503 may be similar to any of the ringsdescribed above in FIGS. 1A and 2A. The second ring 505 includes acircumferential flange 507 that extends between the cement lining 509and the pipe 511, The end 513 of the flange 507 is affixed. to the innerpipe wall 515 by a weld 516, before the lining is placed, to form apressure seal and to hold the ring 505 in place, Both rings 503, 505include a ceramic coating 517, The O-ring that is used to create thepipe joint pressure seal may be located on either ring, as it is shownin FIG. 5C as bing on the first ring 503, and it is shown in FIG. 5D asbeing on the second. ring 505 a. This type of ring with a flange isparticularly useful for curved pipe, tees, ells, reducers, and othernon-linear pipe sections.

A sixth joint lock ring system 601 is illustrated in FIGS. 6A-C. In thissixth system 601, both rings 603, 605 are similar to the second ringdepicted in FIGS. 5A-C. Both rings include a circumferential flange 607which extends between the cement lining 609 and the interior walls 613of the pipes 611, each circumferential flange 607 being affixed to theinterior wall 613 of the respective pipe 611 by a weld 615, which formsa pressure seal to prevent leakage in the event the weld between the twopipes fails. This type of system is particularly useful for retrofittinglined pipes in the field.

During the manufacture process, the rings are manufactured to meet theintended use conditions for the pipe, and the internal liningrequirements for the intended use are determined. The rings are firstinstalled into each end of the pipe at the manufacturing plant, afterwhich the pipe then goes through a machine powered centrifugal cementlining, process, such as is well known in the cement-lined pipeindustry.

At the manufacturing plant customer specified lengths of steel pipe havetheir internal ends ground with a 0.040 chamfer and any excess internalweld seam is sanded smooth. Rings according to a customer'sspecification are fitted with O-rings in the grooves on the outercircumferential surfaces of each ring. A non-toxic, non-petroleum baselubrication is applied to the inside end of the pipe. The ring is thenpressed into position. Once the ring is in place, four one inch longtack welds are applied to the back side of the ring. This procedure isrepeated for each end of the pipe. The pipe is then loaded into thecement lining machine, in which cement slurry is pumped into the pipefrom one end to the other. The pipe is rolled into the machine and spunat an appropriate rate to centrifugally compact the lining to thepredetermined thickness and quality. Since the inserted ring wasmachined to match the required thickness of the applied cement lining,and overall smooth interior surface of the pipe is formed by compressingthe cement lining against the end of each ring, creating a seal and bondto the pipe and the inserted ring. The pipe is removed from the machine,hand finished and capped to go through the curing process. After thecement is cured and reaches its designed strength the pipe section isready for shipping to the customer for installation,

Although the embodiments above are presented from the perspective of thering systems being placed at the time of manufacture, it is possible,albeit somewhat labor intensive, to place the rings in the field when apipe needs to be cut to a shorter length. In the field, after the pipeis cut to length, the next step is remove sufficient amount of thecement lining to allow the ring to be placed into the cut end of thepipe. Removal of at least 1-2 cm extra of the lining is preferred. Withthe cement lining partially removed, and the cut end of the pipeotherwise prepared to receive the ring by removal of buns and sharpedges, the two-piece clamp shown in FIGS. 7A-D and 8A-C are used toposition the ring within the end of the cut pipe. The first clamp part701 shown in FIGS. 7A-D includes two halves 703, 705, which are affixedto the end of the cut pipe using holes 707 in flanges 709 to clamp thetwo halves 703, 705 around the outer wall of the cut pipe end. The firstflange part 701 also includes at least 4 other clamp flanges 713, withholes 715, which are used to secure the first clamp part 701 to thesecond clamp part 717. Preferably, the first clamp part 701 ispositioned to have one edge approximately flush with the cut end of thepipe, with the guide flanges 711 extending away from the cut end of thepipe to support ring being inserted into the pipe. In alternativeembodiments more guide flanges may be included, or they may be excludedaltogether. With the first clamp part 701 affixed to the cut end of thepipe, the ring is partially seated within the cut end as far as it canbe inserted by hand, which will typically be at the point where theO-ring is pressed up against the cut end of the pipe. With the ringpartially seated, the second clamp part 717 is secured to the firstclamp part by aligning the four peripheral holes 719 on the second clamppart 717 with the four holes 715 on the first clamp part. 701 andinserting bolts through the holes 715 in the first clamp part 701 toengage the peripheral holes 719 (which may be threaded, or a nut may beused) of the second clamp part 717. The second clamp part 717 is thendrawn toward the first clamp part 701 by tightening the bolts, and thesecond clamp part 717 will subsequently press the ring in to the cut endof the pipe by compressing the O-ring. Once the ring is fully seated,approximately flush with the cut end of the pipe, the O-ring will createthe desired seal, as described above. As a last step, prior to weldingthe cut pipe to another pipe, is to fill in the space left between theedge of the cement lining and the now-seated ring with appropriatecement for the intended use of the pipe.

FIGS. 9A-D illustrate an alternative embodiment of the first clamp part901. This clamp part is similar to the first clamp part shown in FIGS.7A-D, with the addition of stabilizing flanges 903 which are placedextending along the exterior surface of the pipe. These stabilizingflanges 903 aid in placement of the first clamp part on the pipe,helping to ensure that the bolts of the first clamp part are alignedwith the longitudinal axis of the pipe.

Two sections of pipe are joined by placing them end to end inpreparation for welding. An for rings with a side circumferentialgroove, and O-ring or flexible gasket is placed into the sidecircumferential groove, and two of the first clamp parts, shown in FIGS.5A-D, are used to draw the two sections of pipe together and compressthe O-ring or gasket between the ring surfaces. The joint may then betack welded in preparation for the complete welding of the two pipesections. Each pipe joint is connected in the same manner. The weldjoints formed in this manner may undergo nondestructive weld testing andthe final quality control examination, without concern of cementinclusion or further weakening the cement lining.

Some of the benefits that may be realized from the joint lock ringsystems described above include:

Allows for full penetration joint welding with no internal cement orrubber lining contamination in the weld zone.

Allows for mechanical and non destructive testing of the finished weldjoint.

Allows for a reduction in pipe wall thickness and weld time over partialjoint penetration designs.

Replaces a challenged industry standard for cement lined pipe joining.

Accomplishes a permanent inside pipe shoulder for cement liningcontainment and protection that is out of the weld zone, and no cementpatching is required before or after the joint welding for factoryinstalled rings.

The rings can be factory installed in all straight pipe and loosefittings to be butt welded in the field.

The rings can be easily installed in the field after cutting andbeveling the pipe.

Shop quality internal cement lining patches can be accomplished by□illustration crews for all “cut to fit” field joint applications.

Some designs of the ring system utilize an O-ring gasket that provides asecondary pressure seal that will safe guard the environment in theevent of a weld failure.

The rings can be used with all designs of cement and rubber linings.

The ring base material, ID coatings, and O-ring seal can he IIIengineered and adapted to meet specific pipe grades, various serviceconditions, and fluid types.

Thus, a joint lock ring system is disclosed. While embodiments of thisinvention have been shown and described, it will be apparent to thoseskilled in the art that many more modifications are possible withoutdeparting from the inventive concepts herein. The invention, therefore,is not to be restricted except in the spirit of the following claims.

What is claimed is:
 1. A joint ring system for lined pipes, the systemcomprising: a first pipe and a second pipe, each pipe having, aninterior lining covering substantially all of an interior wall of therespective pipe, the pipes being joined end-to-end; a first ringdisposed within and substantially flush with the joined end of the firstpipe, the first ring being configured to create a first circumferentialpressure seal against the interior wall of the first pipe; and a secondring disposed within and substantially flush with the joined end of thesecond pipe, the second ring being configured to create a secondcircumferential pressure seal against the interior wall of the secondpipe, wherein at least one of the first ring and the second ring isconfigured to create a pipe joint pressure seal against the other of thefirst ring and the second ring.
 2. The joint ring system of claim 1,wherein the interior lining of each pipe comprises one of cement orrubber.
 3. The joint ring system of claim 1, wherein at least one of thecircumferential pressure seals comprises a weld.
 4. The joint, ringsystem of claim 1 wherein at least one of the circumferential pressureseals comprises an O-ring seated in a circumferential groove in theouter circumferential surface of the respective ring.
 5. The joint ringsystem of claim 1, wherein at least one of the rings comprises acircumferential flange extending between the interior lining and therespective pipe.
 6. The joint ring system of claim 5, wherein at leastone of the circumferential pressure seals is formed by a weld betweenthe respective circumferential flange and the interior wall of therespective pipe.
 7. The joint ring system of claim 1, wherein the firstring and the second ring are symmetrically formed and asymmetricallyplaced within the ends of the respective pipes.
 8. The joint ring systemof claim wherein the pipe joint pressure seal comprises an O-ring seatedin a groove formed in an anterior circumferential surface of one of therings.
 9. The joint ring system of claim 1, further comprising a coatingdisposed on the inner circumferential surface of each ring, wherein thecoating is configured to resist corrosion when exposed to a fluidtransported within each pipe during use.
 10. A joint ring system forlined pipes, the system comprising: a first pipe and a second pipe, eachpipe having an interior lining covering substantially all of an interiorwail of the respective pipe, the pipes being joined end-to-end; a firstring disposed within and substantially flush with the joined end of thefirst pipe; a first sealing element configured to form a firstcircumferential pressure seal between the first ring and the interiorwall of the first pipe; a second ring disposed within and substantiallyflush with the joined end of the second pipe; a second sealing elementconfigured to form a second circumferential pressure seal between thesecond ring and the interior wall of the second pipe: and a thirdsealing. element configured to form a pipe joint pressure seal betweenthe first ring and the second ring.
 11. The joint ring system of claim10, wherein the interior lining of each pipe comprises one of cement orrubber.
 12. The joint ring system of claim 10, wherein at least one ofthe sealing elements comprises a weld.
 13. The joint ring system ofclaim 10, wherein at least one of the sealing elements comprises anO-ring seated in a circumferential groove in the outer circumferentialsurface of the respective ring.
 14. The joint ring system of claim 10,wherein at least one of the rings comprises a circumferential flangeextending between the interior lining and the respective pipe.
 15. Thejoint ring system of claim 14, wherein at least one of the first andsecond sealing elements comprises a weld between the respectivecircumferential flange and the interior wall of the respective pipe. 16.The joint ring system of claim 10, wherein the first ring and the secondring are symmetrically formed and asymmetrically placed within thejoined ends of the respective pipes.
 17. The joint ring system of claim10, wherein the third sealing element comprises at least one anteriorcircumferential seal, each anterior circumferential seal disposed on atleast one of the rings and configured to seal against the other ring.18. The joint ring system of claim 17, wherein each anteriorcircumferential seal seats in a groove formed in the anteriorcircumferential surface of each respective ring.
 19. The joint ringsystem of claim 10, further comprising a coating disposed on the innercircumferential surface of each ring, wherein the coating is configuredto resist corrosion when exposed to a fluid transported within thejoined pipes during use.
 20. A pipe comprising: a first ring disposedwithin and substantially flush with a first end of the pipe, the firstring forming a circumferential pressure seal against an interior wall ofthe pipe; and an interior lining covering substantially all of aninterior wall of the pipe, wherein radial thicknesses of the interiorlining and the first ring are substantially the same.
 21. The pipe ofclaim 20, wherein the interior lining of each pipe comprises one ofcement or rubber.
 22. The pipe of claim 20, wherein the circumferentialpressure seal comprises a weld.
 23. The pipe of claim 20, wherein thecircumferential pressure seal comprises an O-ring seated in acircumferential groove in the outer circumferential surface of the firstring.
 24. The pipe of claim 20, wherein the first ring comprises acircumferential flange extending between the lining and the pipe. 25.The pipe of claim 24, wherein the circumferential pressure seal isformed by a weld between the circumferential flange and the interiorwall of the pipe.
 26. The pipe of claim 20, wherein the first ringcomprises a sealing element configured to form a pipe joint pressureseal against a second ring, inset in a second pipe.
 27. The pipe ofclaim 26, wherein the lateral pressure seal comprises an O-ring seatedin a groove formed in an anterior circumferential surface of the firstring.
 28. The pipe of claim 20, further comprising a coating disposed onthe inner circumferential surface of the first ring, wherein the coatingis configured to resist corrosion when exposed to a fluid transportedwithin the pipe during use.
 29. The pipe of claim 20, further comprisinga second ring disposed within and substantially flush with a second endof the pipe, the second ring forming a circumferential pressure sealagainst an interior wall of the pipe.
 30. A method of connecting linedpipes, the method comprising: inserting a first ring into an end of afirst pipe so that the first ring is substantially flush with a firstend of the first pipe, the first ring forming a first circumferentialpressure seal against an interior wall of the first pipe; inserting asecond ring into an end of a second pipe so that the second ring issubstantially flush with the second end of the second pipe, the secondring forming a second circumferential pressure seal against an interiorwall of the second pipe; and welding the first end of the first pipe tothe second end of the second pipe along an exterior circumference of thepipes.
 31. The method of claim 30, wherein inserting the first ring intothe end of the first pipe includes inserting the first ring after aninterior lining is placed to cover substantially all of the interiorwall of the first pipe.
 32. The method of claim 31, further comprisingremoving a part of the interior lining from the first pipe to provide aspace for insertion of the first ring.
 33. The method of claim 31,wherein inserting the first ring into the end of the first pipe includestilling a gap between the ring and the interior lining of the firstpipe.
 34. The method of claim 10, wherein inserting the first ring intothe end of the first pipe includes: securing a first half of a clamp toan exterior of the end of the first pipe; placing the first ring at theend of the first pipe between the first half of the clamp and a secondhalf of the clamp; and drawing together the second half of the clamp andfirst half of the clamp, wherein the drawing, together pushing the firstring into the end of the first pipe.
 35. The method of claim 34, whereinpushing the first ring into the end of the first pipe forms the firstcircumferential pressure seal.
 36. The method of claim 30, whereininserting the first ring into the end of the first pipe includes weldingthe first ring to the first pipe to form the circumferential pressureseal against the interior wall of the first pipe.